add span log for ddl

Signed-off-by: shaoting-huang <[email protected]>

pkg/mq/msgstream/mq_msgstream.go

@@ -373,6 +373,7 @@ func (ms *mqMsgStream) Broadcast(msgPack *MsgPack) (map[string][]MessageID, erro
 		log.Warn("can't broadcast the msg in the backup instance", zap.Stack("stack"))
 		return ids, merr.ErrDenyProduceMsg
 	}
+	log.Ctx(ctx).Info("mq msgsteam broadcast msg size: " + strconv.Itoa(len(msgPack.Msgs)))
 	for _, v := range msgPack.Msgs {
 		spanCtx, sp := MsgSpanFromCtx(v.TraceCtx(), v)
 		ctx2, sp2 := otel.Tracer(typeutil.RootCoordRole).Start(v.TraceCtx(), "Mq_msgstream-broadcast-marshal")